Field of the Invention
The disclosed concept relates generally to machinery and, more particularly, to can decorator machines for decorating cans used in the food and beverage packaging industries. The disclosed concept also relates to mandrels and mandrel assemblies structured to support necked cans.
Background Information
High speed continuous motion machines for decorating cans, commonly referred to as can decorator machines or simply can decorators, are generally well known. A typical can decorator is disclosed in commonly assigned U.S. Pat. No. 5,337,659. It is understood that during the decorating process, the cans are “can bodies,” i.e., shells having a substantially cylindrical body with one closed end and one open end or, in some instances, two open ends. The can decorator includes an in-feed conveyor, which receives cans from a can supply (not shown) and directs them to arcuate cradles or pockets along the periphery of spaced parallel rings secured to a pocket wheel. The pocket wheel is fixedly secured to a continuously rotating mandrel carrier wheel or turret. The turret, in turn, is keyed to a continuously rotating horizontal drive shaft. Radial/horizontal spindles or mandrels, each being rotatable about its own axis, are mounted to the mandrel carrier wheel adjacent its periphery. Downstream from the in-feed conveyor, each mandrel is in closely spaced axial alignment with an individual pocket and undecorated cans are transferred from the pockets to the mandrels. Suction applied through an axial passage of the mandrel draws the can to a final seated position on the mandrel.
While mounted on, and rotating with, the mandrels, the cans are decorated by inking stations such as, but not limited to, inking stations including blankets or digital print heads. That is, the inking station(s) applies ink in a selected pattern while mandrels rotate the cans. Thereafter, and while still mounted on the mandrels, the outside of each decorated can is coated with a protective film of varnish applied by engagement with the periphery of an application roll in an over-varnish unit or digital print heads. Cans with decorations and protective coatings thereon are then transferred from the can decorator for further processing.
Generally, the can bodies and the mandrels are substantially cylindrical. The can bodies have a cross-sectional area that is slightly larger than the mandrel. In this manner, the can fits over the mandrel with the suction applied to the closed end of the can. It is noted that the open end of the can generally does not engage the mandrel. Such mandrels, however, are not structured to decorate can bodies that have been “necked.” That is, a “necked” can has been formed so that the end of the can about the open end has a smaller cross-sectional area relative to most other portions of the can. In this configuration, a cylindrical mandrel sized to pass through the necked open end of the can has a smaller cross-sectional area relative to most other portions of the can. In this configuration, the can is likely to wobble on the mandrel during the decorating process. This is a problem.